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Resin as a continuous and base phase plays a key role in the organic bonded solid lubricating (OBSL) coating. However, the influence mechanism of resin mechanical properties on tribological properties and corrosion resistance of coatings remains elusive. Here, the effect of crosslink density of epoxy resin modified by phenolic resin (Abbr. EP/PH) on the tribological performance /corrosion protection of Mo[S.sub.2] + [Sb.sub.2][O.sub.3]/EP composite coating has been elucidated. The tribology and corrosion properties of the coatings with different crosslink densities were analyzed by SEM/EDS, XRD, XPS, and EIS. The result indicates that when the crosslink density of resin in the coating is moderate of 460 mol/[m.sup.3] and the elastic modulus reaches the highest value of 2217 MPa, the Mo[S.sub.2] + [Sb.sub.2][O.sub.3]/EP composite coating shows low friction coefficient about 0.01, long anti-wear life ([greater than or equal to]480 min), and good corrosion resistance with the higher value of [[absolute value of Z].sub.0.01Hz] (1.92 * [10.sup.10] [ohms] [cm.sup.2])after 72 h of immersion than other coatings. In addition, the too high or too low crosslink density of EP/PH resin is not beneficial to improve the performance of coating. It is because the mechanical strength and toughness of resin with appropriate crosslink density are enhanced greatly, which ensures a tight bond between the filler as a dispersed phase and resin as a continuous phase to form the compact microstructure of coating, which improve the strength and shielding capacity of coating, so the Mo[S.sub.2] + [Sb.sub.2][O.sub.3]/EP composite coating shows good tribological properties and anti-corrosion. Highlights * The effect of resin crosslink density on property of coating has been studied. * The strength of resin with suitable crosslink density are enhanced greatly. * The coating shows good tribological properties and shielding capacity. * The crosslink structure of resin has a great influence on coating properties. KEYWORDS corrosion, crosslink density, fillers, resin, wear and friction, 1 | INTRODUCTION Friction and wear of metal are a hot topic in materials fields. From space machinery to ground equipment, from micro-machinery to super-large aircraft carriers, aviation, ships, nuclear [...]

ZnO film ultrasonic transducers for temperature and stress measurements with dual-mode wave excitation (longitudinal and shear) were deposited using the reactive RF magnetron sputtering technique on Si and stainless steel substrates and construction steel bolts. It was found that the position in the substrate plane had a significant effect on the structure and ultrasonic performance of the transducers. The transducers deposited at the center of the deposition zone demonstrated a straight columnar structure with a c-axis parallel to the substrate normal and the generation of longitudinal waves. The transducers deposited at the edge of the deposition zone demonstrated inclined columnar structures and the generation of dominant shear or longitudinal shear waves. Transducers deposited on the bolts with dual-wave excitation were used to study the effects of high temperatures in the range from 25 to 525 °C and tensile stress in the range from 0 to 268 MPa on ultrasonic response. Dependencies between changes in the relative time of flight and temperature or axial stress were obtained. The dependencies can be described by second-order functions of temperature and stress. An analysis of the contributions of thermal expansion, strain, and the speed of sound to changes in the time of flight was performed. At high temperatures, a decrease in the signal amplitude was observed due to the decreasing resistivity of the transducer. The ZnO ultrasonic transducers can be used up to temperatures of ~500 °C. [ABSTRACT FROM AUTHOR]

The EarlyâMiddle Ordovician peri-Gondwana and Baltica acritarch provinces are easily recognizable, illustrating a clear provincialism of global phytoplankton. However, acritarch assemblages have been reported to become increasingly similar towards the Late Ordovician, revealing a general cosmopolitanism, although, based on more recent studies, their assemblages from Laurentia and Baltica are reported to be rather different from those from peri-Gondwana. In this decade, new acritarch assemblages reported from South America, the Baltic region, Iran and Siberia, as well as the new material from South China and Tarim, provide additional data that help to understand the palaeobiogeographical distribution and evolution of phytoplankton during the Late Ordovician in more detail. The binary dataset was compiled based on published information from about 120 localities in South China, the Middle East, North Africa, South America, India, Bohemia, Avalonia, Laurentia, Baltica, North China, Tarim and Siberia. This dataset was used for Cluster Analysis (CA), Nonmetric Multidimensional Scaling (NMDS), and Network Analysis (NA) to understand acritarch palaeogeography in the Late Ordovician. Re-evaluation of the global palaeobiogeographical distribution of acritarchs revealed their clear provincialism also during the Late Ordovician, particularly in the Katian. The Late Ordovician acritarch provinces were related to global climatic zones. The highly diverse acritarch assemblage normally existed around 30° in the Southern Hemisphere, which is similar to the latitudinal diversity gradient model proposed by Zacaï et al. (2021) for the Late Ordovician. The total diversity of acritarchs was highest and their palaeobiogeographical differentiation strongest in the Katian. The higher acritarch diversity recorded in this time interval may have resulted from their clearly developed provincialism. Acritarch diversity decreased rapidly at the end of the Ordovician, evidently due to the Late Ordovician Mass Extinction (LOME). The relative proportion of endemic taxa in the assemblages in different regions was very high during the main part of the Late Ordovician. However, as a consequence of the LOME, the relative proportion of cosmopolitan taxa increased in the Hirnantian and became higher than in the Sandbian and Katian. Acritarch assemblages from different plates (regions) reacted to the LOME differently and exhibited various diversity trends.

New palynological studies from the Xiaoyangqiao section (Jilin Province, north-east China), which has been selected as an Auxiliary Boundary Stratigraphic Section and Point (ASSP) for the base of the Ordovician, confirms the presence of Goniomorpha Yin 1986 in intervals ranging from the late Cambrian (Furongian) to the Early Ordovician (Tremadocian), and allow us to clarify its morphology and affinities. Despite being compared originally to vesicular microfossils with processes arising from one pole, Goniomorpha lacks an enclosed cavity, so it cannot be classified as an acritarch in the strict sense. Instead, we find that the specimens originally described as Goniomorpha are actually part of a wider spectrum of morphologies that are identifiable as the pharyngeal teeth of priapulid worms. The best-preserved specimens resolve the 'processes' as denticles arising from an arch on the margins of a cuticular pad, sometimes with an extending spur and polygonal microstructure. Closely equivalent forms have been reported from Cambrian assemblages of small carbonaceous fossils (SCFs) and in situ on Burgess Shale specimens of the priapulid Ottoia. The findings from the Xiaoyangqiao section extend the taphonomic range of Cambrian-type SCFs into the Ordovician, and provide the first evidence for priapulids from the Ordovician of northern China. More generally, our results demonstrate the reciprocal insights from palynological and SCF-type processing for identifying problematic microfossils. [ABSTRACT FROM AUTHOR]

In this paper, a series of Zn1−xInxNNi3 samples were synthesized by a solid–gas reaction route under NH3 atmosphere and the same was crystallized in Pm3m space group. The magnetic properties was investigated by means of zero-field-cooling and field-cooling magnetization and studied the Zn-site doping effect, only when 0.3 ≤ x, the superconductivity rapidly disappears. In element doping affects the electron pairing and strongly suppresses the superconductivity. No uniform solid solution can be obtained at low In content (x ≤ 0.2), instead micrometer-scaled ferromagnetic Zn0.7In0.3NNi3 domains formed embedded within a superconductive ZnNNi3 bulk, showing chemical phase separation of superconductive ZnNNi3 and ferromagnetic Zn0.7In0.3NNi3. Only at a high In content (0.3 ≤ x), the uniform ferromagnetic solid solution Zn1-xInxNNi3 is formed. [ABSTRACT FROM AUTHOR]